Due to the synchronization requirements, which result from the possibility of driver exchanges and deadheading, the DRSPMS falls into the category of routing problems with synchronization constraints. This relatively new research field has gained increasing attention during the past two decades.
For a comprehensive review and classification of synchronization in vehicle routing up to 2011, we refer to [1]}.
As pointed out by [1]}, existing publications on vehicle routing with synchronization focus primarily on load synchronization (e.g., for transshipments) and on temporal synchronization of customer visits. Research addressing the temporal and spatial synchronization of non-autonomous vehicles to enable movements is still scarce.
This so-called movement synchronization is relevant in various settings and applications, including N-echelon routing problems [3]}, active-passive vehicle routing problems [4]}, [5]}, and the routing of workers and vehicles [6]}, [7]}.
In the following, we survey only literature that considers movement synchronization in the context of vehicle and crew routing and scheduling as contained in the DRSPMS.
